1st stage switch; tank valve breathing

[Kevin Carlisle]

Agreed with Dale C. No tech diver prefers the valve breathing, and if you so it often you obviously lack some skills. Feathering the valve is easy to do. Now on a trimix dive two weeks ago we did take one of my regs apart for repairs during the dive, no harm done but it is getting serviced.

 

[DevonDiver]

I'm pretty sure the article was referring to feather breathing. It does now (I contributed substantially to that wiki).

 

[beanojones]

Yeah feathering (and to a lesser extent reg switching) are basically the reasons why SM can be considered safer than BM.

There is basically no way to get a the back regs in BM without removing the harness, and that is just too much for most situations.

 

[rjack321]

Jim, I'd expect that the same is true for transmitters, isn't it? Does anybody use transmitters for Sidemount anyways?

Yes and no
No serious tech diver uses transmitters. They are so so reliable but more to the point a rediculously expensive gimmick. Most of us have between 6 and a dozen regs...

 

[Johanan]

Thank you, friends! You did it again - my questions are answered. I signed up for a SM course in July. Can't decide, should I have it with PADI or with SSI? The instructor can do both.

Regards, J.

 

[Colliam7]

If I understand correctly, by "regulator switching" it is meant removing the 1st stage from one cylinder and installing it to another cylinder underwater. Have you ever tried to do that?

Yes, in fresh water, and it is a trip. I decided to practice it just so I could say I had done / could do it. And, yes, I disassembled my reg afterward and cleaned it - not a big deal, but something I wanted to do, beyond simply replacing the filter.

What would be the effect of water entering the 1st stage and would an ACD (automatic closure device) be of any help?

It is not a big deal for a small amount of water to enter the second stage. Most of it will end up coming out in the pressurized air that you breath. Maybe the reg will breath a bit wet on the first breath or two, then you don't really notice it (I hardly notice it anyway). The issue really is NOT a conspicuous amount of water somehow 'flowing' into the regulator first stage aperture while the first stage is exposed, it is the fact that you by necessity trap a small amount of water between the reg aperture and the cylinder valve aperture (probably, a bit more with a DIN first stage than a yoke first stage) when you connect the first stage to the other cylinder. When you open the valve, that (small amount of) water gets forced into the first stage). But, it just isn't that much water.

Is breathing directly from a tank valve similar to breathing from a free-flowing regulator that is taught in the OW course?

Similar. But, personally, I find breathing from a free-flowing second stage to be a bit easier than breathing from a tank valve. Of course, that may just be because when I breath off a tank valve that is accessible / in front of me, I feather the valve and adjust the flow, which I cannot necessarily do with a free-flowing second stage where the first stage is behind me.

For fun, go to Steve Bogaerts website (gosidemount.com), click on the 'Galleries' tab near the top of the home page menu, then click on 'Video-Gallery' and watch video # 9. - 'Advanced Side Mount Skills'. Bogaerts demonstrates breathing off a malfunctioning second stage by feathering the valve, then changing the second stage in-water, then breathing off a cylinder valve. Great video! I encourage my OW (recreational) SM students to try breathing off a valve during the course. It is instructive, and actually fun for them to try.

A suggestion - on your own, take an extra cylinder - without a regulator - with you on your next dive - it can be a small cylinder like a 19 cf or a 30/40 cf. Then, when when you are at depth, take you second stage out, and try breathing off the valve on the small cylinder. Because of the position and angle of the (small) aperture on the valve opening, you will find a very specific 'sweet spot'. Once you do, breathing off a cylinder valve is pretty easy (a bit salty in seawater, perhaps). Don't worry about water back -flowing into the cylinder, as long as you don't breath it dry.


---------- Post added February 26th, 2013 at 05:26 PM ----------

I know there are some instructors during "advanced sidemount" courses that teach breathing off a regulator hose (removing the second stage if failed), then breathing from the actual cylinder valve. As well as swapping first stages underwater. Currently the aforementioned is way out of my depth however i hope to get there one day

You may be referring to the Steve Bogaerts video that I mentioned previously. It is really a great, and very educational, tool. It is like most skills that seem 'out there' - if you practice it in a controlled environment, you find it is actually pretty easy. So, I would not necessarily say that it is way out of your depth. Try it, in a controlled situation (confined water OR open water) where you have plenty of primary cylinder gas ready at hand, and use a smaller auxilliary bottle. It really isn't hard to do. I did it for grins and giggles for the first time in Bonaire several years ago - I just took an extra 63 cf bottle - no regulator, not even any rigging - with me on a dive, and tried it in shallow (30 ft) water until I could do it comfortably, then took it to 130 ft to see it it was harder - it wasn't. The biggest challenge was carrying the extra bottle and tying up my hands / arms to hold onto it, while adjusting my buoyancy to accommodate the extra weight at the strat

 

[Johanan]

Thanks! This video #9 is a perfect demonstration of all the techniques I was asking about. Thank you for pointing at it.